The State of Overgrowth Mechanics

I think I am pretty close to what special mechanics I want to build the set with. Let's go over where things stand.

1. Mutate. When a creature with mutate is the target of a spell or ability it gets a +1/+1 counter.

Mutate is primary in green and red. It's secondary in black and blue. White does not have access.

I'm happy with the mechanic itself, but rethinking the name of it. While the mechanic does represent magical mutation, the fantasy concept of mutation also tends to involve wild variations as a result. The initial incarnation of mutate did this, but I've simplified it because it was even more parasitic than this. So I think I want to give the mechanic a name that indicates growth. It will be fun trying to find a word that hasn't already been used on green cards.

2. Reave. Reave is a kicker-type ability that allows you to exile a card from your graveyard as an additional casting cost. As with kicker abilities, the caster will be rewarded with a bonus effect if they pay the reave cost.

Reave appears only in red and black and on a couple of artifacts. It is very important to note that the bonus effect is written in such a way that it cares only if a card left your graveyard to trigger. That means it doesn't need to be the reave kicker that triggers it. Recursion spells of any kind will also count for reave cards. This matters in higher rarities, where the power of a reave bonus increases on the basis of the number of cards that have been exiled.

Also, while every card with reave on it will inherently have a bonus effect, there will also be cards with abilities that care about cards leaving your graveyard that don't have reave on them. This allows for permanents with recurring triggers to reward repeat use of reave.

3. Fecund. When a non-token creature with fecund dies, create a token copy of it.

Fecund will appear on all five colors, but primarily in green and white.

It's not the most innovative mechanic, but I feel like it's a very intuitive way of representing quick reproduction. Fecund will appear only on small animal creatures, not sentient races.

4. Suppress. When a creature is the target of suppress, it is unaffected by external power and toughness changes.

Suppress will appear only in blue and white. A creature can be suppressed for just a turn or for longer.

I have a feeling the rules text will need more tweaking after playtesting, but I like how the concept of it serves as a counter to mutate and reave bonuses that buff creatures.